TIP 2: LAYER MASKS
Today we’re moving on to the next tip for Photoshop beginners, Layer Masks. Layer Masks are what you should be using almost every time you think about using the eraser tool.
If you have a photographic image that you want to make adjustments to, for example removing a background, you might think that the eraser tool is the right man for the job. This is rarely the case. Using the eraser tool is what’s known as destructive editing – as in, you are removing important data from the image without any way of getting it back – this is destructive.
“Hold on”, you might say, “what about Undo, or the History panel?” Well, this works to a point, but once you have used all of your history states, you might find that you’re left with eraser strokes you can’t remove and an unusable image.
Instead, select your image, go to Layer> Add New> Layer Mask> Reveal All, or click on the layer mask button (A) in the layers panel*. A white box will appear on your layer next to the layer thumbnail (B). This is your layer mask.
To use it, click on the white box and make sure that there is a border around it – this lets you know that any changes you make will be applied to the mask, not the image. You will notice that your foreground and background colours change to black and white; this is normal, as layer masks can only be black or white – black hides, white reveals.
Select the brush tool and make sure that your foreground colour is black (If it isn’t, press X – this handy shortcut switches the foreground and background colours around). Start to paint onto your layer mask and you should see your image start to disappear where you have painted. Now switch to white by pressing X, and paint back over what you masked.
You should immediately see the benefit of using layer masks over erasing. The image information is not deleted, just hidden, which means if you make a mistake, you can just paint it back in. Now you just have to have a steady hand and patience…
*If you are having trouble creating a layer mask, you might need to make sure your layer is not still a background layer. If it is, you will see a little white padlock icon within the layer. To remedy this, double click the layer, press OK to the modal box that appears, and you should be able to create a mask from then on.